Electrically operated photoflash attachment



Jan. 1, 1935.' s. MENDELSOHN ELECTRICALLY OPERATED PHOTOFLASH ATTACHMENT Filed Jan. 15, 1932 2 Sheets-Sheet 1 SE C O/VD R 1. I 0 0 0 0 0/ 0 0 0 0 W M m f 4 3 2 0 M a Jan. 1, 1935. s. MENDELSOHN 1,986,513

ELECTRICALLY OPERATED PHOTOFLASH ATTACHMENT Filed Jan. 15, 1932 2 Sheets-Sheet 2 INVENTOR :5. MEA/DELfiOHA/ ATTOR Y Patented Jan. I, 1935 E UNITED STATES PATENT OFFICE ELECTRIGALLY OPERATED PHOTOFLASH ATTACHMENT Samuel Mendelsolm, Brooklyn, N. Y.

Application January 15, 1932, Serial No. 586,931 14 Claims. (01. 67-29) This invention relates to photographic appa- The lag difference in the time relation between ratus and relates more particularly to a device the operation of the shutter and the occurrence for causing instantaneous illumination and the of the flash makes the operation of devices as operation of a camera shutter simultaneously. heretofore employed unsatisfactory and imprac- The practice of taking photographs with artitical. I have found that the time lag is due to 5 ficial light such as that which is termed flash the fact that when electrical energy is passed light, is well known in the photographic art. A through thecold filament a certain time interval recent development in connection with the takis required to heat the filament and it was ing of. flash light pictures is a device called a therefore diilicult in mechanisms heretofore pro photoflash lamp such for example as shown in posed to operate the shutter at exactly the right 10 Patent 1,776,637 issued September 23, 1930. time.

The photoflash lamp consists of a transparent In accordance with the present invention, I bulb in which is sealed a filament or heater elep d a method of Operating a DhOtOfleSh p ment and around this element is disposed a by first initially heat the filament to a quantity of combustible aterial ch as iuperature insufficient to ignite the flash material, 15 minum foil. The bulb contains a gas such as d then Passing a am of ele t cal curpure oxygen which promotes ombu ti n of th rent through the filament sufllcient to raise its foil when electrical energy is passed through the temperature t ignite t o wh flew o emfilament, heating the same to a temperature suflirent also operates the shutter so that the operaciently high to ignite the flash-producing mation o the S r and flashing Operation are 20 terial. simultaneous.

A photofiash lamp is similar in general con- The invention will be more clearly understood struction to an incandescent electric lamp and y e ce t the a pany de p o t is usually provided with a standard screw thread s th r w th th a mpany n drawin in w i h:

base and may be operated by application to the Fi 1 is a p sp tiv v w f a am ra havi 25 ordinary commercial line voltage. For the purthe prese t invention pp d t pose of practicing photography in places where Fig. 2 is a diagram of the electrical wiring emit is not convenient to use line voltage, the photo- Dl ye operate the mechanism shown in Fig. 1; flash lamp may be operated by means of a suit- Fig. 3 is a modification of the wiring diagram I able dry cell. When attempting to use a photoshown in Fig. 2 and 30 flash lamp, while taking what is known as a Fig. 4 is an oscillograph curve showing the snapshot or high speed exposure, itisobvious that variation of intensity of light during the operameans must be provided so that the camera shuttion of a photoflash bulb.

ter be open to make the exposure at the time the As shown in Fig. 1 of the drawings, the invenflash occurs. The ordinary flashlamp produces tion may be applied to a camera 10 having the 35- an intense light for a very brief period of time, usual shutter 11 provided with a shutter setting generally for about .060 of a second. During this arm 12 and shutter release arm 13. Adjacent to interval the light produced reaches its highest the release arm is a solenoid 14 which may be peak and then follows a downward intensity contained in a holder 15 and suitably attached to curve. the face plate 16 of the camera. On the box 17 40 It will be evident that for the best results, the of the camera is attached a holder 18 which may camera shutter should be open when the highest contain a relay and a switch to be later described intensity of light is produced. Attempts have and a battery 19 may be suitably supported by been made to mechanically operate the camera clips on the holder 18. The holder 18 is pros ut e at t time the flas Occurs and by p g vided with a socket 19 to receive a photofiash lamp 45 actuated elements it has been possible to operate 21. A switch 22 is provided to pass a. heating ourthe .shutter at about the time the current passes rent through the filament of the photoflash lamp hr h e h r lem nt t produce a flash. and an actuating switch 23 serves to cause a flow It has been found, however, that a time lag 00- of current for the operation of the shutter and curs between the operation of the shutter and the photoflash lamp. 50

the actual ignition of the light giving material The above general description gives an outline and in cases where the shutter operates at high of the mechanism for operating a photoflash lamp speed, it is impossible to obtain entirely satissubstantially simultaneously with the opening of factory results with means heretofore employed. the shutter and it will be obvious that the ar- In cases where the shutter operation is relatively rangement of the operating parts constituting slow, the exposure is very often made during the disclosed construction may be varied in acthe period when the light is the least intense cordance with the particular construction of the and the same is true if the shutter operates too camera employed.

fast or the respective operations are otherwise The electrical system will be more clearly out of time. understood by reference to Fig. 2 which shows a 60 diagram of the circuit including the photofiash lamp 21, a cut-out solenoid 18', operating sol'enoid 14,-switches 22, 23 and battery 19. Filament or heater element 24 of the photoflash lamp is connected to the battery 19 on one side by means of a conductor 25 through switch 22. The opposite side of the battery is connected by a conductor 26 with one end of the coil of the solenoid 18'. The opposite end of the coil of the solenoid 18' is connected by a conductor 27 to the opposite end of the filament 24. When the switch 22 is closed, current will fiow through flie filament 24 but, by reason of the solenoid winding, a resistance is placed in circuit with the filament and it is therefore not heated to a temperature sufficient to ignite the flash material.

When the switch 22 is closed, electrical energy normally flows through a conductor 28 to one side of the solenoid 1'4 and thence through a conductor 29, switch 31, conductor 26 and to the battery 19. When the current flows through the circuit for preheating the lamp, however, armature 33 which constitutes a part of the switch 31 is moved away from its contact 34 thus breaking the circuit to the solenoid 14. After the filament has been preheated, actuating switch 23 is operated and cur-- rent flows through a conductor 35, through the filament 24, conductor 25 and to the battery 19. The opposite side of the battery is connected by the conductor 26 with the switch '23.

Inasmuch as the conductor 35 is connected to the conductor 27 between the solenoid 18 and the filament 24, the closing of the switch 23 will short circuit solenoid 18' and the armature 33 thereof will'engage contact 34 causing a flow of current through the solenoid 14 to actuate its armature 37 and thereby operate the shutter 11 through contact with shutter arm 13.

The above described electrical system includes first a primary or preheating circuit including the filament 24, conductor 25, battery 19, conductor 26 and the coil of the solenoid 18', the solenoid 18' also operating to break the circuit including the shutter actuating solenoid 14.

A secondary circuit which operates to heat the filament sufiicient to ignite flashlight material and includes the filament 24, conductor 25, switch '22 (which is closed) battery 19, conductor 26, switch 23 and conductors 35 and 2'7. This circuit which operates to cut-out the solenoid 18', permits armature 33 to return under action of any suitable means such as a spring 20 and to close the circuit including solenoid 14 thereby actuating the shutter 11.

A shutter actuating circuit including the solenoid 14, conductors 28, 25, battery 19, conductor 26, solenoid switch 31 and conductor 29.

In Fig. 3 a modified form of the circuit is shown including a photofiash lamp 40, an actuating solenoid 41, a double throw switch 42, a single throw switch 43 and a battery 44.

Current is caused to fiow in a filament 45 when switch 43 is closed and current for preheating the filament flows through a conductor 46 connected to one side of the filament 45 and to one side of the battery 44. The opposite side of the battery is connected with a conductor 47 which leads to one end of a resistance element 48.

The opposite end of said resistance element is connected by a conductor 49 with the opposite side of the filament 45. It will be evident that current flowing from the battery when passing through the resistance 48 will be reduced and may be made insufficient to heat the filament to a temperature to ignite flashlight material, but

means sufiicient to elevate the temperature of the filament ready for a flashing operation. When the double throw switch 42 is actuated, an arm 51 thereof connects conductors 47 and 49 thus directly connecting the filament with the battery and short circuitingthe resistance 48 and an arm 52 of the switch connects conductor 47 with a conductor 53 leading to one end of the coil of the armature -41. The opposite end of the coil of said armature is connected by conductor 54 with conductor 46 which leads to the battery 44. When the switch 42 is actuated therefor, the resistance 48 is cut out and the solenoid actuated to move its armature 55 and operate the shutter release arm 13.

The modified construction above described includes first a primary or preheating circuit consisting of the filament 45, conductor 46 battery 44, conductor 4'7, resistance 48 and conductor 49.

A secondary circuit for heating the filament to ignite flashlight material including the filament 45, conductor 46 battery 44, conductor 47, one side of the double pole switch 42 and conductor 49.

A shutter actuating circuit including the solethe curve of high intensity of the flash. An I ideal condition is reached when the camera shutter is opened between A and B and in ases where the time lag is not taken care of, t e shutter may open .020 of a second too soon a d the'picture will be taken between A and C or where it is necessary to mechanically adjust the shutter with respect to the time of the flash, the shutter may, by reason of friction or lost motion, be opened at any point between B and D, in which case altho an exposure may be made, the best results are not attained.

It has been found that the time lag which is due to the necessary heating of the filament before the fiash occurs, has heretofore resulted in uncertain conditions whereas by reason of the present invention, the operating of the shutter is timed to make the exposure during the period in which the flashlight material gives the most intense light.

Altho the preferred embodiment of the invention is shown and described herein, it is understood that modifications may be made therein without departing from the spirit and scope of the invention as set forth in the appended claims.

What is claimed is:

1. A device for operating a camera shutter and a photofiash lamp comprising an electrical circuit including the heater element of said lamp, means for causing a fiow of electrical energy through the heater of said lamp to elevate the temperature thereof, means for actuating a camera shutter, means for increasing the amount of electrical energy passing through said heater to heat it to flashing temperature and means for causing said second and third mentioned means to operate simultaneously.

2. A device for operating a camera shutter and a photoflash lamp simultaneously, comprising a ergy, means for passing electrical energy through said primary circuit and means for simultaneously passing electrical energy through said secondary circuit and said shutter actuating circuit.

3. A device for operating a photoflash lamp in time relation to the operating 01 a camera shutter which comprises a member Ior actuating said shutter, means for preheating the'filament of said lamp, means for passing electrical energy throughsaid lamp to operate same and means for moving said member to actuate said shutter. l4. A device for operating a photoflash lamp and a camera shutter comprising an electrical circuit, a source of electrical energy for said circuit, the heater element oi. the photoflash lamp in said circuit, another circuit including a solenoid for operating a camera shutter, means for causing a fiow or electrical energy. from said source through said element, a resistance to reduce the amount of current fiow through said element and means for cutting out said resistance and causing a flow oi'current through said element and said solenoid to cause the latter to actuate said shutter simultaneously with the operation of said lamp.

5. A device for operating a photoflash lamp and a camera shutter comprising an electrical system, including a source of electrical energy, a circuit for preheating the heater element of a lamp, a circuit including electrically operable means for operating a shutter, a circuit for the now of current to operate said lamp and means for causing a flow of electrical energy in said circuits tofiash said lamp and actuate said electrically operable means.

6. A device for operating a photoflash lamp and a camera shutter simultaneously, comprising a source of electrical energy, means for passing an amount of electrical energy through the heater in said lamp to heat the same to a temperature insufilcient to operate the lamp, a camera shutter, a circuit for the passage of an amount of electricalenergy through said heater to flash said lamp, electrically operable means for actuating said shutter and means for passing electrical energy through said heater to operate said lamp and actuate said shutter;

7. A device for operating a photoflash lamp and a camera shutter simultaneously, comprising a source oi electrical energy, means for passing an initial preheating current through the filament of said lamp, means for passing .an operating current through the filament of said lamp, a camera shutter, electrically operable means for actuating said shutter and means for simultaneously passing a current through said filament and said means for operating said'shutter.

8. A device for operating a camera shutter and a photoflash lamp simultaneously, comprising a source of electrical energy, an electrical system including the heater element of the lamp, electrically operable means for operating a shutter, means for passing an amount or said electrical energy through said element to heat the same to a temperature insufilcient to fiash' said lamp, means for passing an amount of said electrical energy through said element sufiicient to flash said lamp, said last named means operating to cause electrical energy to actuate said shutter operating means.

9. An electrical system for operating a camera shutter and a photoflash lamp simultaneously, comprising a source of electrical energy, a circuit including the heater element of said lamp and means for limiting the amount of current fiow through said element, means for causing current to fiow through said circuit, another circuit including said heater element for the flow of current therethrough in the absence of said resistance, another circuit including electrically operable means for actuating a camera shutter and means for causing a simultaneous fiow of current through said last two circuits.-

10. A device for operating a camera shutter and a photoflash lamp or the like simultaneously, comprising means for heating the igniter of said lamp to a temperature below the temperature required to flash the lamp, means for heating said igniter to operating temperature, means for operating a camera shutter and means for simultaneously operating said second and third mentioned means.

11. A system for operating a camera shutter and a photoflash lamp or'the like simultaneously, comprising a source or electrical energy, a circuit including the igniter of said lamp and the coil of a solenoid, another circuit including said igniter for a fiow of current short-circuiting said coil, another circuit including another solenoid for operating a camera shutter and a switch adapted to be opened upon a flow of current through said firstmentioned solenoid, means'tor causing a fiow of current through said first named circuit to preheat the igniter and breakthe last named circuit and means for causing a flow of current through said second and third mentioned circuits to the exclusion of a flow of any appreciable amount of current through said first named circuit.

12. The method of operating a camera shutter during the operation oi! a photoflash lamp, which comprises causing a flow oi! an amount of electrical energy through the filament ot a photoflash lamp insufilcient to fiash the lamp, causing the flow oi. a greater amount of electrical current through the filament to flash the lamp and in utilizing the second fiow of current to operate the camera shutter.

13. The method of operating a camera shutter during the'operation of a photoflash lamp which comprises causing the fiow of an amount 01' electrical current through the filament of a photofiash lamp .insufilcient to flash the lamp but sumcient to elevate the temperature of the filament, causing a second fiow of current through the filament while heated to fiash the lamp and in utilizing the second fiow of current to operate a camera shutter.

14. A device for operating a camera shutter and 

